1. Technical Field
The present invention relates to an inflatable vehicle occupant restraint system, and is particularly directed to an air bag assembly including a valve member on an air bag reaction canister for venting inflation fluid away from the reaction canister to control inflation of an air bag.
2. Background Art
A vehicle occupant restraint system having an inflatable air bag is known. Typically, an inflation fluid source such as a pyrotechnic gas generant, a stored gas supply, or a combination of the two, releases inflation fluid in response to a signal indicative of vehicle deceleration of at least a predetermined magnitude. The released inflation fluid is directed from the inflation fluid source into an inflatable air bag located in an air bag canister to inflate the air bag. In known vehicle occupant restraint systems, the released inflation fluid has a pressure which varies as a function of the ambient temperature in the vicinity of the inflation fluid source. This pressure variation occurs because the inflation fluid is sensitive to ambient temperature variations. Accordingly, the air bag tends to inflate faster when the ambient temperature is relatively high and to inflate slower when the ambient temperature is relatively low. Preferably, the air bag should inflate at the same rate over a wide ambient temperature range.